Low profile, high flowthrough smoke chamber

Abstract

A low profile optical smoke chamber structure with a top cover incorporating airflow slots, an intermediate annular air channel, a depending light shield wall surrounding an interior detection chamber where the top cover is interengagable with a base member where the light shield wall is spaced from the base member so as to provide minimal deflection of ambient airflow into the detection chamber while preventing impingement of ambient light therein.

1 . A low profile smoke chamber assembly for a photoelectric hazardous condition detector, comprising:
 a) a base member of a first select peripheral height and a cover member of a second select peripheral height, said base member and cover member being releasably interlockable to form an integrated housing having a height less than the combined heights of the first and second select heights enclosing a smoke chamber;   b) said base member including a photoelectric source mounting member and a co-planar, angularly off-set sensor mounting member, each of said mounting members including feedthrough apertures for electrical communication to an adjacent surface;   c) said cover member including a substantially continuous interior wall projecting to a height greater than the second select height where said inner wall establishes a peripheral boundary of a detection chamber contained within, and an outer wall of the second select height, said outer wall including a plurality of vertically oriented airflow slots having a height less than but substantially equal to the second select height, an annulus established between said outer wall and said inner wall for communicating air from said plurality of vertically oriented airflow slots into and out of said detection chamber, said detection chamber including a light source mounting assembly and a co-planar light sensor mounting assembly angularly offset from each other.   
     
     
         2 . The low profile smoke chamber assembly according to  claim 1  where the light source mounting assembly and the light sensor mounting assembly each include at least one feedthrough for communication of electrical power to a structure underlying the base member. 
     
     
         3 . The low profile smoke chamber assembly according to  claim 1  where the light sensor mounting assembly incorporates a particle/dust trap. 
     
     
         4 . The low profile smoke chamber assembly according to  claim 1  further including spurious light reflection reduction elements. 
     
     
         5 . The low profile smoke chamber assembly according to  claim 4  further where the spurious light reflection reduction elements include serrated surfaces and baffles. 
     
     
         6 . The low profile smoke chamber assembly according to  claim 1  further comprising mounting prongs projecting below the base member for mounting to an underlying printed circuit board. 
     
     
         7 . The low profile smoke chamber assembly according to  claim 1  where the base member and cover member are cylindrical and the outer wall is established by a plurality of alternating exterior columns and recessed pillars forming radially oriented air gaps therebetween. 
     
     
         8 . A bifurcated, low profile smoke chamber, comprising:
 a first member and a second member, said first member and second member being interengagable to establish an interior detection chamber having a substantially open area and a select height, said detection chamber being shielded from impingement of ambient light by a light trap wall depending from said first member, said wall having a height less than that of the select height to provide a substantially continuous perimetric channel for ingress and egress of ambient air relative to the detection chamber, said detection chamber incorporating spaced apart, angularly offset, and substantially coplanar light source mounting means and light sensor mounting means,   said first member including a substantially annular airflow path exterior of said light trap wall and interior of an outer perimeter wall, said outer perimeter wall incorporating a plurality of perimetric airflow slots disposed at an angle substantially orthogonal to said light trap wall.   
     
     
         9 . The bifurcated low profile smoke chamber of  claim 8  where surfaces of the detection chamber are serrated to minimize reflection of light from a light source. 
     
     
         10 . The bifurcated low profile smoke chamber of  claim 9  where the light source is a light emitting diode. 
     
     
         11 . The bifurcated low profile smoke chamber of  claim 8  where the light sensor mounting means includes a dust trap. 
     
     
         12 . The bifurcated low profile smoke chamber of  claim 10  where the interior detection chamber incorporates a light shield baffle projecting from said second member to trap light generated by the light emitting diode when the light is directly launched onto the interior wall. 
     
     
         13 . The bifurcated low profile smoke chamber of  claim 12  where the second member includes prongs for mounting to an underlying structure. 
     
     
         14 . The bifurcated low profile smoke chamber of  claim 8  where each of the light source mounting means and light sensor mounting means include at least one feedthrough for lead wires. 
     
     
         15 . A smoke chamber comprising a multi-piece cooperative structure featuring a top element and a base element, the top element including a multi-wall structure defining a vented exterior wall and a depending interior wall, the interior wall defining an interior detection chamber incorporating substantially coplanar mounting assemblies to secure at least a light source and a receptor sensor;
 the top element further comprising a plurality of alternating columns and gaps with a recessed pillar forming a base of each gap and slotted openings forming the sides of the gap, an annular airflow channel disposed between the slotted openings and the depending interior wall to establish a shield from entry of ambient light into the interior detection chamber while providing an airflow path with minimal obstruction for quick and efficient ingress and egress relative to the interior detection chamber.   
     
     
         16 . The bifurcated low profile smoke chamber of  claim 15  where the base element includes prongs for mounting to an underlying structure. 
     
     
         17 . The bifurcated low profile smoke chamber of  claim 16  where the base element includes a light source mounting means and a light sensor mounting means each incorporating at least one feedthrough for lead wires.